Dynamo-electric machine.



M. W. W. MACKIE.

DYNAMO BLEGTEIG MACHINE.

on FILED JULY z4.x9o1.

APPLIUATI 909,197. Patented Jan. 12, 1909y MATTHEW WILLIAM WALBANK MACKIE, OF EALING, ENGLAND.

DYNAMIC-ELECTRIC MACHINE.

No. 909, 197. Sp ecication of Application filed July 24,

Letters lPatent.

1907. Serial No. 386,247.

Patented Jan. 12, 1909.

To all 'whom it may concern:

Be it known that l, l\i[A'rTHEw WrLLiAM WALBANK Macina, a sub'ectof the King of Great Britain and Ireland, residing at Ealing, in the county of M iddiesex, England, have invented Improvements in or Connected with Dynamo-Electric l\lachines,.oiI which the followin is a s eciiication.

This invention as re erence to improve- .ments in or connected with electric supply l systems wherein a constant or practically constant electr-emotive f'orce is maintained between the terminals of a multipolar dynamo electric machine by varying the strength of the field, magnet poles, or some of them, by a demagnetizing winding, upon variation in the speed of the machine from a predetermined speed corresponding` to normal Voltagev One arrangement for this pu rposeis described in the specification of another application for Letters Patent filed by me dated 24th August 1906, Serial No.

`331830, according to'Which some of the poles lterminals of the machine practically coustant. For controlling the flow of current through the main Winding, the electro-motive force therein is opposed by a counter electro-niotive` force produced by a secondary battery in such a manner that at a pre determined speed of the machine, corres ioni ling to normal voltage, no or practically no current will flow through the main winding but upon increase ofspeed and conse( uent increase in the electro-motive force oi the machine, current will be caused to iow through the main winding in opposition to the counter electro-motive force of the sccondary battery and more or less dcmagnetizo the magnet poles upon which the winding is placed so as to thereby reduce the electrol motive force of the machine to about the normal' amount, the said secondary battery being in some cases arranged to simultaneously supply a work circuit to which it is connected, or to act as a reserve source of supply therefor, if such circuit is to be normally supplied by the dynamo by ,wonnecting it across the brushes thereof, and further is adapted to be interchanged at will, if desired, with another secondary battery arranged to be charged in another work'cireuit directly supplied by the dynamo while the first named secondary battery is in use for the pur ose des/m'ibed.V

how according to the present invention in order that the action of the main or demagnetizing winding between one brush of the machine and the second or regulating secondary battery used for opposing the flow of cur-- *renththrough such winding may be readily adjusted so as to obtain any desired voltage across the brushes of the dynamo machine to suit different working conditions, as for example to adapt the machine for use with different types of secondary batteries, without for this purpose having to alter or vary the construction of the windin I provide in the circuit between the one en of the said main winding and the secondary battery connected thereto, a device such for example as a plurality of cells containing lead plates dip ping into dilute sulfuric acid, or a supplementary set of secondary cells having no such cells added to that of the secondary battery connected to the said winding and opposing the flow of current through the main or demagnetizing winding together with the E. M. F. necessary to overcome theresistance of the demagnetizing winding and pass the maximum regulating current through the said demagnetizing winding, shall e ual the E. M.F. required to charge the ot ersecondary battery connected across the brushes device I provide means, such as a switch, whereby the amount of the counter electromotive force o posed to the total eieetromotive force of t 1e machine b such device can be readily varied to suit 'fferent requirements.

By the means described, the main Winding can be made ci small ohlnic resistance' so that it can be caused to act in the required manner with any re uired predetermined g difference of potential etwecn its ends, and the difference of otential between the terr minals of the mac ine above the normal dif l ference at which the regulating action of the storage caps r:ity or practically no storage capacity so that in either case the E. M. F. of

ofthe machine, and in connection with such main windinjjr will commence, can be made variable and small required, say about two volts, so as to suit the particular secondary batteries in use.

'lhe invention is specially applicable in connection with dynamo-electric apparatus of the kind referred to for train lighting but is also applicable in cases where motors, or other translating devices are to be used in the circuit supplied by the dynamo and, it may be, by the secondary battery.

The accompanying drawing illustrates diagramrnaticnlly one application of the invention, o. being the dynamo or generator, b the shunt winding of the field magnet, c the demagnothing/winding d the secondary battery supplyinv the wort( circuit g and the E. M. F of which op )oses the E. M. F. of the dynamo through the wimling c, h the secondary battery which is connected across the brushes el, a" ofthe generator c during char(r` ing and is ada ted to be interchanged wit 1 the secondary battery d, the battery interchanging switch, and lc an automatic cut-out controlled. by a centrifugal governor m for l 'which can be added to that of the regulating when the speed opening the dynamo circuit o that necessary the armature falls below for supplying the voltage necessary for charg-` ing the Secondary battery h, 'ny is the supple` mentary set of secondary cells employed according to this invention, and p a switch for cutting one or more of the said cells n into and out of circuit as required? As will be understood, with a demagnetizing winding c of a given resistance, a certain difference of potential must exist between its op osito ends before current can flow theret ough. This winding further, to be effective, must be such that it will produce the desired regulating eii'ect rapidly, as soon as the aforesaid difference of potential is but slightly exceeded. Therefore, in order that an excessive difference of potential shall not exist between the brushes of the machine for a given dynamo speed when the secondary batteries d and h for use therewith are replaced by secondary batteries of lower voltage, the secondary cells n, or one or some ci' them can be switched out of circuit to enable the voltage between the brushes che to be reduced and at the same time insure that the predetermined difference of potential at the-terminals of the denlagnetizing'i winding e for regulating purposes shall not be altered. Similarly, when `secondary batteries of greater voltage are to be used in iieufof batteries of less voltage, one or more of the supplementary cells n, or one or more additzional ccllsfare put in circuit with the said Winding. `lnthis `way the machine is enabled to supply the independent work circuit ncluding the 'secont ary battery to be charged, directly with current at the required constantvoltage.V

It is to be understood that the invention l maintained practically constant b may be used with a dcmagnetizing winding on some only or all of the'poles oi the vield magnet oi' a dynamo electric machine.

l. ln an electric supplvsystem wherein the voltage ol' a dynamo is maintained practically (':onstant by a demagnctizing winding and a secondary battery opposing the flow of current therethrough, the conibination with the denmgnetizing winding and secondary battery arranged in series with each other between the brushes of the dynamo of means adapted to supplement the E. M. F. of the said secondary battery and whereby the voltae of the vnaino can be altered without a tering the t emagnetizing winding.

2. In an electric supply system wherein the voltage of a dynamo is maintained praetically constant by a demagnctizing winding and a secondary battery opposing the flow oi current therethrough, the combination with the demagnetizing winding and secondary battery arranged in series with each other between the brushes of the dynamo, of a supplementary set of cells the E. M. F. of

secondary battery.

3. In an electric supply` system wherein the voltage of a dynamo 1s maintained`prac,l

tically constant'by a den'mgneiizln winding and a secondary battery opposing t 1e llow of current therethrough, the combination with the demagnetizing winding and secondary battery arranged in series with each otherfY between the brushes of the dynamo, oi", a su plen'ientary set of electric cells thev E. M. of which can be added in whole orin part to that of'the regulating secondary battery.

4. ln an electric supply system wherein the voltage of a shunt wound dynamo is netizing winding and a secondary attery opa demag-r posing the flow of current therethrough, the combination with the demagnetizing wind.

ing and secondary with each other battery arranged in seriesetwecn the brushes of the dynamo, of a supplementary set of electric` cells and means w icreby one or more of the same can be cut into and outof thc circuit of ,i

the lRaid demagnetizing'windingjand scbondn ary battery at will. l y l, 5. In an electric supply systernfwhc'rel the voltage of a shunt wou"ridnnultlpolalfI d namo is maintained practicall f constaijit'liy a demagnetizing winding ani a *secon'rlary'v` r battery opposing the flow ofcurrent ,there-' the combination wit-litho de'magf'.I

through y i netizlng winding and secondarwr battery ranged in series with cach other between the lls, and a switch adapted to brushes of the dynamo, of a supplernentaryy set of electric ce cut said cells into demagnetizing winding` and teryin any required order.

6. In an electric supply system wherein and out of circuit with said l secondary' bat; l

the voltage of a dynamo is maintained practically 'constant by a demagnetizin Windin and a secondary battery opposingr t 1e How o current therethrough, the combination with the demagnetizing Winding and secondary battery arranged in series with each other be tween the brushes of the dynamo, of a supplementary set of secondary cells of no or practically no capacity, and means wherebyone or more ofy the same can be cut into and ou t of. circuit at will with said demagnetizing winding and secondary battery.

7. In an electric supply system wherein the voltage of a dynamo is maintained practically constant by a demagnetizin windin and a secondary battery opposing t 1e flow o current therethrough, the combination with the demagnetizing Winding and secondary battery arranged in series wlth each other between the brushes of the dynamo, of a supplementary set of secondary cells of no or practically no capacity and a switch adapted to cut said cells mto and out of circuit with said demagnetizing Windin and secondary battery in an required or er.

8. In an eectric supply system wherein the voltage of a shunt Wound dynamo is maintained practically constant by a demagnetizingwinding and a secondary battery o posing the flow of current therethrough, t combination with ,the demagnetizing winding and secondar battery arranged in series with each other etween the brushes of the dynamo of a supplementary set of cells, the volta e of eachl o which is equal to the individua increments orrdeclementssof voltage re uired at the brushes of the dynamo, sa1d cel s being arrarggqdfto be placed in series withs'aid demagnuzing winding and sec- OndariT battery 9. In an electric suppl)r system wherein the voltage of a shunt wound dynamo is maintained practically constant hy a dcmagv netizing winding and a secondary'battery opposingthe How of current therethrough, the combination with the demagnctiaing wiud ing and seconder battery arranged in series with each other betweergihe brushes of the dynamfri of a supplementary set of secondary cells of no or practically no capacity, theA volta e of each of which is equal to the individua increments or decrcments of voltage re uired at the brushes of the dynamo, said ce s being arranged to b e placed in series with the said` demagnetizing 'winding and secondary battery.

10. In `an electric supply system wherein the voltage o f a shunt wound, multipolar dy namo is maintained ractically constant by a demagnetizing win -ng on some of its poles and a secondary battery opposing the flow of current therethrough, the -combination with the demagnetizing winding, the secondary battery arranged in serieswith each other between the brushes of the d namo, and a distributing system connecte to the terminals of said secondary battery, of a su i lementary set of secondary cells arranged Eetween the secondary battery and dema netizing winding so as to assist the action o the secondary batte and a switch device whereby 'one or more o the supplementary cells can be put in and out of action.

Signed at London England this 28thday of June 1907.

MATTHEW WILLIAM lWLBANK MACKIE. 

